1. Field of the Invention
This invention pertains to the general field of fluid control devices used in water irrigation and similar distribution systems. In particular, it provides a new and improved valve for automatically and alternatingly switching fluid flow between two downstream lines from a common upstream source.
2. Description of the Prior Art
The practice of diverting water flow in irrigation systems has been known since ancient times. Water available in limited amounts from a single source is alternately channelled to different areas downstream in order to provide water flow for a given length of time in a quantity sufficient to meet the specific needs of each area. As these needs are met, the flow is diverted to another area in the distribution system with comparable requirements. The principle behind this practice is the same whether a large volume aqueduct or a garden sprinkling system is involved.
In order to implement this practice, it became necessary to devise means for stopping the water flow through a given channel and diverting it to an alternative one. Thus, different devices have been invented, ranging from ancient manual ditch gates to sophisticated modern automatic valves.
For instance, U.S. Pat. No. 470,489 to Henkel (1892) describes a water cut-off device that automatically diverts the flow of water from one conduit to another after a predetermined amount of flow. The invention uses a deflector actuated by a lever mounted on a wheel that is turned by the water passing through the first conduit. Though automatic, the device has to be reset after each use. This patent is directed primarily to delivery systems for the storage of rain water.
U.S. Pat. No. 3,425,437 to Knerr (1969) shows a fluid control device for automatic laundry machines that incorporates a valve mechanism to divert flow between two conduits. The mechanism is set manually at the beginning of the cycle and is then automatically controlled by fluid pressure in cooperation with a set of springs and levers that change the position of the valve between washing stages. If not reset, the mechanism is inoperative. This apparatus is designed for use strictly in conjunction with washing machines.
In U.S. Pat. No. 3,570,539 (1971), Herring teaches a gate for stopping the flow of material from an input channel or, alternatively, for allowing flow through the gate and to one of two output channels. The gate is operated and kept in place by a lever that can be actuated either manually or automatically. The invention does not include an apparatus for switching the direction of flow at the occurrence of predetermined events.
U.S. Pat. No. 3,667,498 to Mizuno (1972) illustrates a new sprinkling-system valve that permits the sequential flow of water first to a branch line and then to a primary line for continuing distribution downstream. The valve contains a pivoted vane that is spring-biased to close the branch conduit and to open the main conduit. When the water pressure is momentarily interrupted, the vane switches to the alternate position and the next direction of flow is through the main conduit. The result is the automatic switch of flow to the next downstream station when the water is temporarily shut off from the station that is currently being irrigated. The valve must be reset between cycles to re-establish flow to the branch station.
In U.S. Pat. No. 3,841,346 (1974), Amblank describes an apparatus for diverting water flow from the bath tub faucet to the shower head and vice versa. After being switched manually from one option to the other, the device is kept in position by the pressure of the water delivery system. The invention is directed exclusively to plumbing applications.
In U.S. Pat. No. 4,178,954 (1979), Klieves shows a diaphragm valve that alternatingly switches the direction of flow between two lines every time the water pressure is interrupted. This result is obtained automatically by a cycling mechanism that is alternately cocked into a position to open the previously closed portion of the valve. This apparatus requires no resetting and is designed especially for irrigation purposes.
Finally, U.S. Pat. No. 4,807,665 to Schiel (1989) discloses an electromagnetically driven valve for selectively receiving fluid flow from two separate inlets. This valve contains no mechanism for automatically switching the path of flow and is not sensitive to fluid pressure. Although designed for general application, it could not be effectively used as a substitute for your invention.
It is evident from the foregoing that the prior art is either very complicated, inasmuch as it utilizes complex mechanical and electrical devices to switch the course of fluid flow, or not automatic, requiring periodic manual resetting. Therefore, there still exists a need for a simple device that addresses these problems.